001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017
018package org.apache.logging.log4j.core.async;
019
020import org.apache.logging.log4j.status.StatusLogger;
021import org.apache.logging.log4j.util.PropertiesUtil;
022
023/**
024 * Strategy for deciding whether thread name should be cached or not.
025 */
026public enum ThreadNameCachingStrategy { // LOG4J2-467
027    CACHED {
028        @Override
029        public String getThreadName() {
030            String result = THREADLOCAL_NAME.get();
031            if (result == null) {
032                result = Thread.currentThread().getName();
033                THREADLOCAL_NAME.set(result);
034            }
035            return result;
036        }
037    },
038    UNCACHED {
039        @Override
040        public String getThreadName() {
041            return Thread.currentThread().getName();
042        }
043    };
044
045    private static final StatusLogger LOGGER = StatusLogger.getLogger();
046    private static final ThreadLocal<String> THREADLOCAL_NAME = new ThreadLocal<>();
047
048    abstract String getThreadName();
049
050    public static ThreadNameCachingStrategy create() {
051        final String defaultStrategy = System.getProperty("java.version").compareTo("1.8.0_102") < 0
052                ? "CACHED" // LOG4J2-2052 JDK 8u102 removed the String allocation in Thread.getName()
053                : "UNCACHED";
054        final String name = PropertiesUtil.getProperties().getStringProperty("AsyncLogger.ThreadNameStrategy");
055        try {
056            final ThreadNameCachingStrategy result = ThreadNameCachingStrategy.valueOf(
057                    name != null ? name : defaultStrategy);
058            LOGGER.debug("AsyncLogger.ThreadNameStrategy={} (user specified {}, default is {})",
059                    result, name, defaultStrategy);
060            return result;
061        } catch (final Exception ex) {
062            LOGGER.debug("Using AsyncLogger.ThreadNameStrategy.{}: '{}' not valid: {}",
063                    defaultStrategy, name, ex.toString());
064            return ThreadNameCachingStrategy.valueOf(defaultStrategy);
065        }
066    }
067}